http://en.wikipedia.org/wiki/Rhetoric
i don't have much to say on this topic yet, except:
- there are at least two opposite connotations to this subject; one is that it is almost sinful, a prioritizing of appearances over reality, style over substance, a Machiavellian attempt to manipulate rather than to share information (although even with this connotation one would be advised to learn about rhetoric, so as to protect oneself against it, even if not to employ it offensively); and the other that it is a civic virtue, somewhat like etiquette, the art of adapting what you want to communicate into a form that will ease its understanding by listeners.
- rhetoric was extra important in ancient Greece, where oratory, rather than writing, was said to be the main mode of scholarly and civic communication. Since then we've shifted partially to writing, and indeed there is a study of how to write persuasively; and we also have broadcast media, and indeed there is a study of how to write or speak persuasively over a broadcast. However, now we have the internet; is there yet a study of how to persuade on internet forums?
on the last question i havent yet found any excellent links. Do send me some if you'd like.